diff --git a/examples/correlation_matrices/sampler.cpp b/examples/correlation_matrices/sampler.cpp
index 9a0756ebe..f57dd6513 100644
--- a/examples/correlation_matrices/sampler.cpp
+++ b/examples/correlation_matrices/sampler.cpp
@@ -89,10 +89,7 @@ void write_to_file(std::string filename, std::vector<PointType> const& randPoint
     std::cout.rdbuf(coutbuf);
 }
 
-bool is_correlation_matrix(const MT& matrix){
-
-    const double tol = 1e-8;
-
+bool is_correlation_matrix(const MT& matrix, const double tol = 1e-8){
     //check if all the diagonal elements are ones
     for(int i=0 ; i<matrix.rows() ; i++)
     {
@@ -102,7 +99,7 @@ bool is_correlation_matrix(const MT& matrix){
 	}
     }
 
-	//check if the matrix is positive definite
+    //check if the matrix is positive definite
     Eigen::SelfAdjointEigenSolver<MT> eigen_solver(matrix);
 
     if(eigen_solver.info() != Eigen::Success)